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STM32L433xx Functional overview

The main features of the touch sensing controller are the following:

• Proven and robust surface charge transfer acquisition principle

• Supports up to 21 capacitive sensing channels

• Up to 3 capacitive sensing channels can be acquired in parallel offering a very good

response time

• Spread spectrum feature to improve system robustness in noisy environments

• Full hardware management of the charge transfer acquisition sequence

• Programmable charge transfer frequency

• Programmable sampling capacitor I/O pin

• Programmable channel I/O pin

• Programmable max count value to avoid long acquisition when a channel is faulty

• Dedicated end of acquisition and max count error flags with interrupt capability

• One sampling capacitor for up to 3 capacitive sensing channels to reduce the system

components

• Compatible with proximity, touchkey, linear and rotary touch sensor implementation

• Designed to operate with STMTouch touch sensing firmware library

Note: The number of capacitive sensing channels is dependent on the size of the packages and

subject to I/O availability.

3.21 Liquid crystal display controller (LCD)

The LCD drives up to 8 common terminals and 44 segment terminals to drive up to 320

pixels.

• Internal step-up converter to guarantee functionality and contrast control irrespective of

. This converter can be deactivated, in which case the VLCD pin is used to provide

the voltage to the LCD

• Supports static, 1/2, 1/3, 1/4 and 1/8 duty

• Supports static, 1/2, 1/3 and 1/4 bias

• Phase inversion to reduce power consumption and EMI

• Integrated voltage output buffers for higher LCD driving capability

• Up to 8 pixels can be programmed to blink

• Unneeded segments and common pins can be used as general I/O pins

• LCD RAM can be updated at any time owing to a double-buffer

• The LCD controller can operate in Stop mode

3.22 Random number generator (RNG)

All devices embed an RNG that delivers 32-bit random numbers generated by an integrated

analog circuit.

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